Performance of the Structural Lightweight Concrete with Metakaolin Exposed To Elevated Temperature

This study examined the effect of the elevated temperature on the mechanical and physical properties of the structural lightweight concrete (SLC) specimens produced by substituting cement with metakaolin (MK) at proportions of 5%, 10%, 15% and 20% by weight. The changes of the compressive and splitting tensile strength of the series were determined at the end of the 3, 7, 28-day curing periods. Up to 15% w/w MK addition demonstrated the optimum contribition to the strength development in all three curing periods. Nondestructive tests, such as ultrasonic pulse velocity (UPV), porosity, sorptivity, results have supported this conclusion. Also, the specimens that cured 28-day were heated in an electric furnace up to 400,600 and 800 o C and kept at these temperatures for one hour. The specimens were cooled in the furnace. Then the relative compressive strength values of these specimens were determined. While the loss of compressive strength was observed in all series depending on the elevating temperature, 15% w/w MK addition series was showed the highest compressive strength value. However, especially at a temperature of 600 ° C, increasing percentage of MK, the series have less affected by the elevated temperatures. The scanning electron microscope (SEM) studies have also supported these findings.

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Mahyuddin B. Ramli, Alonge O. Richard, (2016):Characterization of Metakaolin and Study on Early Age Mechanical Strength of Hybrid Cementitious Composites. Construction and Building Materials,121,599–611.